HiCan someone please tell me crankshaft balancing specs for a 1200 ul flathead. Stock crank and standard pistons.Also does anybody know what the baffle plates do on the crankcases. Any info would be greatful.

In my U the oem-piston had no oil-control rings and baffle only on the front sylinder. After installing pistons with oil-control rings, the front cylinder showed lack of lubrication. After removing the baffle, the cylinder showed no evidence of lack of lubrication. Might be a coincident, but Haynes answer seams logical to me.

Cooky6660, If you haven't figured it out yet, you soon will..... Baffles were installed at the factory many years ago so as to baffle future restoration mechanics. They also appear to perform an auxiliary function, to wit, control oil. Very likely this thread will continue for pages and not ever give you any more knowledge than that. By the way, I too have a very firm conviction based on indisputable facts as to what the true function is.... anonymous

The HD motor went through a lot of design changes in the late 30's through 40's. IE, baffles, placement of forked rod, addition of oil control rings to the pistons, actually collecting oil from the engine sump and recirculating it, adding a bypass valve to the oil pump to cut down oil circulation through the engine at low speeds. Those seem to be the salient points.They went from a design where oil left the engine out the tailpipe to actually trying to keep it inside the engine/oil tank circulation system. Also the sales department can't be left out of the formula. It was a time where one touted your engineering advancements, and HD was perceived to be behind the crowd on that point, in that Indian and the Brits were recirculating engine oil for several years before HD started to. Now, I've never ridden any length of time behind a constant loss HD, but, I've got to assume they left a light blue haze behind them when the pump was set up right. If you've going to tout your engineering advancements in sales literature, (recirculating oil system) I'm thinking you're going to want to ditch the "blue haze" of the earlier machines to prove the superiority of the new system. Tied to this would be an actual decrease in oil consumption as an additional sales point. So, I'm going to assume the changes in the oiling system were to improve oil consumption, for good mechanical reasons as well as sales reasons.Which finally leads us to the baffles and their raison de etre. To Reduce oil consumption. Likewise the rod placement, to reduce oil consumption. With the swapping of the forked rod, it help block the "flinging" of oil up onto the rear cylinder, so the baffle could be removed. The low speed bypass valve, another ploy to reduce oil consumption at low speed, helping to remove the "blue haze" from the tailpipe of a new type machine, differentiating it from older, "obsolete" machines. (sales pitch here, ditch your old VL, buy the new Improved UL). As for one theory of the narrow slot created by the baffles creating a vacuum to help lubricate cylinders/pistions, I offer these thoughts. Ever pull the timing plug on a running harley? Get a little oil mist in your face? Right. Inside those crankcases it's a hurricane confined. Oil is being flung from the only source, the rod journals, radially, in all directions, including up at the bores. No extra inducement is needed to get it there. Witness all later Harleys with no baffles, and much higher performance and heat loads on the pistons.They are only oiled by "flung" oil from the rod journal. They do, however, have high quality oil control rings, which the harleys of the late 30's early 40's DID NOT HAVE. An interesting point, that, as they existed. Hastings first marketed the 3 piece oil ring in 1935. So better technology was certainly out there. I think that about ends the rant. In my mind, at least, it compels me to believe that the baffles were to limit oil to the pistons/cylinders. Plus, the Old harley dealer who attended HD service schools in the 40's also told me this was what they were taught in the schools. DD

Frankenstein used a who lot of words to say exactly what I said. In addition to his findings let me further explain the shape of the baffles. Look at them and you will see that the outside edge is deeper than the center. A trough so to speak. Oil gathered in this trough and when the bottom of the piston skirt dipped into it oil was collected on the piston skirt. This providing the correct amount of lube on the piston. I usually don't waste this many words on any subject but it seems that Panic couldn't understand my brief explanation.

He is, in this "explanation", as completely wrong as he is about everything else.Rather than discuss it, why don't some of you actually do something beyond his imagination: look at a baffle plate, and then tell me why it doesn't do what he says.If Mr. Haynes would limit his remarks to matters within his comprehension, we'd never hear from him again.

OK panic, For the sake of brevity, the slots through the baffles which slope to the lowest points allow any oil to drain back into the crankcase. The "trough" holds nothing. Is that what your looking for?Robbie

That is how it was explained to me by a very old, factory trained wrench. He told me the trough was there so the skirt could dip in in and collect oil. Seriously thinking, would the baffles need a trough if the plan was simply for the oil to flow off the baffles? I don't know it all. But when a factory wrench with sixty years of experience tells me something I tend to believe him.

The explanations of the baffle use is as it was explained to me many years ago on an Indian motor. The baffles limited the amount of oil thrown onto the cylinder walls and also directed the oil to the piston skirt front to back so as to lubricate the piston. The man who explained it then beat the baffles out of a set of Indian cases because as he explained it, the new rings had an oil control ring so as to wipe excess oil more efficiently. I'll try to understand your explanation Panic if you would explain it rather than just say it ain't so.

We should vote on it.If enough people agree, the factory engineers will rise from their graves and modify the original plans.That is how the world works, isn't it? There are no facts, just opinions? And everyone's is equal, just like "Dancing With the Stars"?

I've found that attempting to 'explain" something to a person who is waiting to criticize anything I say, and who wouldn't understand the comment anyway is a waste of everyone's time.It it what it is, whether you understand it or not. It doesn't depend on whether I convince you.

If you run out of things to do, you can decide that Pi = 4, like the Mississippi state legislature did.

Panic, you are right on point with part of your statement. If enough people repeat it, it will be fact. I have carried this explanation around for many years, because it makes sense to me. Each step as explained makes sense to my limited intelligence on the subject. Maybe if you would try and explain your facts some of us would be able to grasp what it is you are trying to say. I haven't said you are wrong, only that I would like to hear your view on the inner workings. I get the impression you feel as though your thoughts are so far out of my limited knowledge that I would only be confused.I may have missed an edit here somewhere but I did not see any explanation on your part.